Patent GB-670692-A (GB)
Title: Improvements in a control means for steam operated power generating systems
IPC: F01K13/02
Filed: 1947-08-08
Abstract: 670,692. Power-generating systems. ASKANIA REGULATOR CO. Aug. 8, 1947. [March 27, 1944] No. 22140/47. Class 122(iii). [Also in Group XXIX] In a steam-operated power generating system the supply of fuel and air to the steam boiler is controlled by means which respond to changes in the load on the engine and in the rate of supply of energy to the engine. Thus, the steam boiler 1 of an electrical-generating plant is controlled by a master regulator 40 which is sensitive to the pressure in the steam main 4 and the power output of a D.C. generator 3 driven by a turbine 2, and which controls the supply of fuel and air to the boiler through regulators 41, 42 respectively. The master regulator comprises a pivoted beam 45, subject on one side to the pressure of a bellows device 49 connected by a pipe 49<SP>1</SP> to the steam main 4 and on the opposite side to the loads of an adjustable spring 48 and an electromagnetic device including a core 51, the centre leg of which has current and voltage windings 52, 53 connected to the power leads 56 of the generator 3, and a pivoted jet-pipe 43 subject on one side to the movement of the beam 45 through linkage 44, 47 and on the other to a loading spring 58. The pipe 43 directs a jet of fluid into either of two pipes 88, 89 connected to the opposite ends of a servomotor cylinder 86, the piston of which operates a crank 95 on a shaft 94 having a gearwheel meshing with a rack 92 on a rod 100 carrying cams 90, 97, 98. The cam 90 serves as a follow-up for the pipe 43 and the cams 97, 98 serve to deflect Deflection of the pipe 60 is resisted by the pressure on the right-hand side of a diaphragm 61 exposed through a pipe 63 to the pressure in a device 19, said pressure being a measure of the consumption of oil in the burners 11 disposed in a circuit including oil inlet and outlet pipes 12, 13 respectively provided with meters 15, 16 connected to differential means 17, the revolutions of the shaft 18 of which determine the pressure in the device 19. Deflection of the pipe 70 is resisted by the resultant pressure on the opposite sides of a diaphragm 71 said sides being connected by pipes 74, 75 to a flow-measuring tube 76 disposed in the air supply pipe 21 from the blower to the combustion space of the boiler. The flow of oil is controlled by a valve 14 regulated by a servomotor 66, the supply of pressure fluid to which through pipes 64, 65 is controlled by the jet-pipe 60, while the supply of air to the boiler is controlled by a servomotor 80 supplied with pressure fluid through pipes 77, 78 from the jetpipe 70 and which, through a shaft 22, controls the speed of the blower 20 or the position of shutters regulating the discharge therefrom. The pipes 65, 77 to the servomotors 66, 80 respectively are provided with non-return valves 105, 107 and corresponding byepass valves 106, 108, to ensure that the air supply to the boiler is increased in advance of an increase in the supply of oil and reduced later than a decrease in the oil supply. The exhaust of the products of combustion from the boiler is controlled by a damper 24 regulated by a servomotor 31 supplied with operating fluid by a jet-pipe 26, the position of which is controlled by a spring 35 and the pressure on a diaphragm disposed in a case 36 connected by a pipe 37 to the combustion space. An increase in the load on the generator 3, results in increased opening of the governor-controlled steam supply valve 5 to the turbine and a fall in steam pressure in the main 4 and, through the beam 45, anti-clockwise movement of the jet-pipe 43 which directs pressure fluid the jet-pipes 60, 70 of the regulators 41, 42. through the pipe 89 into the lower end of the servomotor cylinder 86 and this results in downward movement of the rod 100 and the cams 90, 97, 98 thereon. The cam 90 recentres the pipe 43, while the cams 97, 98 permit anti-clockwise motion of the jetpipes 60, 70 resulting in increased supplies of oil and air to the boiler.